Dates in information dictionary are not prefixed by "D:"

[paulish]

PDFs which are created by Acrobat PDFMaker have CreationDate and ModDate dates prefixed by "D:"

An example:

/ModDate(D:20171222131004+03'00')

Dates generated by mPDF don't have this prefix.
An example:

/ModDate (20190906012700+00'00')

As result they don't pass PDF/A validation by veraPDF library.

I fixed this locally by changing writeInfo of MetadataWriter.php:
$this->writer->write('/CreationDate ' . $this->writer->string('D:'.date('YmdHis') . $offset)); $this->writer->write('/ModDate ' . $this->writer->string('D:'.date('YmdHis') . $offset));

The PDF reference also states in 3.8.3 that 'D:' is optional but strongly recommended.

[peterdevpl]

I made a PR for this :)